The blaze apparently started in a vacant business in the strip mall at 728 S. Atlantic Blvd., then spread to two shops on either side, fire officials said. Smoke seeped into five other businesses, officials said.

About 34 firefighters, including assisting units from Alhambra, South Pasadena and Los Angeles County, responded when the first call came in at 1:49 a.m. It took about 30 minutes to extinguish the blaze, Monterey Park Fire Department Battalion Chief Jim Birrell said.

Investigators were working Wednesday to determine the cause, he said.

Several of the business owners said they had repeatedly warned the mall’s owner about the vacant business being left unlocked. But Chapman Lew, the property’s manager, said it was too early to say how the fire started.

Most of the damage was contained to the back of the attic above the vacant storefront. Charred bits of roof were strewn in the lot behind the building and windows of some of the businesses where blackened by the flames.

The worried owners of the seven damaged businesses – all Chinese restaurants and beauty shops – gathered in the parking lot in front of the mall Wednesday morning to await word from their insurance companies and to learn when utilities would be restored.

“I don’t know when I’m going to open,” said Annie Huang, a hairdresser who owns Annie’s Hair Design. “I have a lot of payments to make.”

Owner Chris Lee opened Liang’s Kitchen three doors down from the vacant storefront a month ago. He said he will have to start over now because of the fire.

“All the food has to be thrown away,” said Lee. “The smell is really bad. The smoke stains need to be cleaned, and it’s really bad in the kitchen.”